Without limiting the scope of the invention, its background is described in connection with current methods of etching titanates, as an example.
Titanate materials (e.g. lead zirconate titanate, PbTiZrO.sub.3, hereafter abbreviated PZT), because of their electrical and mechanical properties, have found many uses in the field of electronics. The very high dielectric constants exhibited by many titanate compounds make them useful as the dielectric material in capacitors, especially in the miniature capacitors which are built into many integrated circuits (e.g dynamic RAMs). Many titanate materials also have a positive temperature coefficient of electrical resistance, which allows devices to be made which protect electrical motors from damage due to over-current conditions. The piezoelectrical properties of these materials are widely used, as in the precise control of the length of laser cavities, for example. Microminiature structures which incorporate titanate materials are being used to sense infrared radiation, obviating the need for bandgap detector materials which require cryogenic cooling to sense the infrared.
Titanate materials are often etched during the fabrication of the electrical devices which exploit their beneficial properties. A method used to etch titanates should generally do so without introducing damage which would unacceptably change the properties of the material on which the function of the eventual devices depends. In addition, an anisotropic etch method is usually desired so that detail in the etch mask pattern is preserved. Contamination of the titanate material (and/or nearby materials) by the etch method usually cannot be tolerated.
Heretofore, in this field, titanates have been etched by isotropic wet etching, ion-milling, plasma etching or laser scribing. Laser scribing is a method wherein selected portions of the material are damaged and weakened by exposure to intense laser radiation and then removed.